Gadgets · 2026-11-11

Forearm as a Trackpad: Radar Bracelet Lets You Control a Smartwatch with Gestures

Researchers at North Carolina State University have built EpiPad, a prototype radar bracelet that turns the wearer's forearm skin into a touch panel for controlling a smartwatch.

✨ What the researchers built

Researchers at North Carolina State University developed EpiPad, a prototype that turns the wearer's forearm into a touch panel. Users can scroll pages, zoom images, and tap items on a smartwatch without touching its tiny screen.

The system is based on a compact millimeter-wave radar sensor about 5 by 4 millimeters in size, worn on the wrist like a bracelet. Instead of a touchscreen, the radar tracks finger movements and measures pressing force on the forearm skin by detecting changes in reflected signals.

📌 How it works

To recognize gestures, the researchers developed a special signal-processing method based on the phase dynamics of millimeter waves and used lightweight machine learning models. Before first use, the user goes through a short calibration that takes 3 minutes and 54 seconds.

🔹 Test results

In experiments with 20 volunteers, gesture recognition accuracy was 92.8%, and pressing force detection accuracy was 90.2%.

In real-time comparison tests, the researchers compared a regular touchscreen, tilt-based cursor control, and EpiPad. Their prototype outperformed the other methods in efficiency and error rate.

🔸 Will it reach the market

For now, it is a prototype in the form of a bracelet with an open circuit board. In the future, the components could be built into regular smartwatches. Scientists estimate that the cost of the functional components, including the radar array, could be less than $10.

The technology could also work for screenless devices, such as smart glasses, using the skin as a surface for input commands without buttons or displays. The developers stress that this is a concept tested on a small group of people, not a finished commercial product.

Sources: 🔗 DOU/dev.ua